Support Plate for Localized Heating in Thermal Processing Systems

ABSTRACT

Support plates for localized heating in thermal processing systems to uniformly heat workpieces are provided. In one example implementation, localized heating is achieved by modifying a heat transmittance of a support plate such that one or more portions of the support plate proximate the areas that cause cold spots transmit more heat than the rest of the support plate. For example, the one or more portions (e.g., arears proximate to one or more support pins) of the support plate have a higher heat transmittance (e.g., a higher optical transmission) than the rest of the support plate. In another example implementation, localized heating is achieved by heating a workpiece via a coherent light source through a transmissive support structure (e.g., one or more support pins, or a ring support) in addition to heating the workpiece globally by light from heat sources.

PRIORITY CLAIM

The present application claims the benefit of priority of U.S.Provisional Application Ser. No. 62/645,476, titled “SUPPORT PLATE FORLOCALIZED HEATING IN THERMAL PROCESSING SYSTEMS,” filed on Mar. 20,2018, the entirety of which is incorporated herein by reference for allpurposes.

FIELD

The present disclosure relates generally to thermal processing systems.

BACKGROUND

A thermal processing chamber as used herein refers to a device thatheats workpieces, such as semiconductor wafers. Such devices can includea support plate for supporting one or more semiconductor wafers and anenergy source for heating the semiconductor wafers, such as heatinglamps, lasers, or other heat sources. During heat treatment, thesemiconductor wafers can be heated under controlled conditions accordingto a preset temperature regime.

Many semiconductor heating processes require a wafer to be heated tohigh temperatures so that various chemical and physical transformationscan take place as the wafer is fabricated into a device(s). During rapidthermal processing, for instance, semiconductor wafers can be heated byan array of lamps through the support plate to temperatures from about300° C. to about 1,200° C., for times that are typically less than a fewminutes. During these processes, a primary goal can be to heat thewafers as uniformly as possible.

SUMMARY

Aspects and advantages of embodiments of the present disclosure will beset forth in part in the following description, or may be learned fromthe description, or may be learned through practice of the embodiments.

One example aspect of the present disclosure is directed to a thermalprocessing apparatus. The apparatus includes a plurality of heat sourcesconfigured to heat a workpiece. The apparatus includes a rotatablesupport plate operable to support the workpiece during thermalprocessing. The rotatable support plate includes a transmissive supportstructure configured to contact the workpiece. The transmissive supportstructure includes a first end and a second end. The first end of thesupport structure is arranged to support the workpiece. The apparatusincludes a light source operable to emit coherent light through thetransmissive support structure such that the coherent light heats aportion of the workpiece contacting the transmissive support structure.

Other example aspects of the present disclosure are directed to systems,methods, devices, and processes for thermally treating a semiconductorsubstrate.

These and other features, aspects and advantages of various embodimentswill become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the present disclosure and, together with thedescription, serve to explain the related principles.

BRIEF DESCRIPTION OF THE DRAWINGS

Detailed discussion of embodiments directed to one of ordinary skill inthe art are set forth in the specification, which makes reference to theappended figures, in which:

FIG. 1 depicts an example rapid thermal processing (RTP) system having asupport plate with spatially arranged low transmission zones accordingto example embodiments of the present disclosure;

FIGS. 2A and 2B depict an example support plate with spatially arrangedlow transmission zones according to example embodiments of the presentdisclosure;

FIG. 3 depicts a flow diagram of a process for heating a workpiecethrough a support plate with spatially arranged low transmission zonesaccording to example embodiments of the present disclosure;

FIG. 4 depicts an example RTP system with a rotatable support plate anda coherent light source according to example embodiments of the presentdisclosure;

FIG. 5 depicts an example base with spatially arranged low transmissionzones according to example embodiments of the present disclosure;

FIG. 6 depicts an example of coherent light heating a workpiece througha rotatable support plate with spatially arranged low transmission zonesaccording to example embodiments of the present disclosure;

FIG. 7 depicts an example rotatable support plate with a ring supportaccording to example embodiments of the present disclosure; and

FIG. 8 depicts a flow diagram of a process for heating a workpiece basedon a rotatable support plate and a coherent light source according toexample embodiments of the present disclosure.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments, one or moreexamples of which are illustrated in the drawings. Each example isprovided by way of explanation of the embodiments, not limitation of thepresent disclosure. In fact, it will be apparent to those skilled in theart that various modifications and variations can be made to theembodiments without departing from the scope or spirit of the presentdisclosure. For instance, features illustrated or described as part ofone embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that aspects of the presentdisclosure cover such modifications and variations.

Example aspects of the present disclosure are directed to support platesfor localized heating in thermal processing systems to uniformly heatworkpieces, such as semiconductor workpieces, opto-electronicworkpieces, flat panel displays, or other suitable workpieces. Theworkpiece materials can include, for instance, silicon, silicongermanium, glass, plastic, or other suitable material. In someembodiments, the workpieces can be semiconductor wafers. The supportplates can be used to support workpieces in various thermal processingsystems that implement a variety of workpiece manufacturing processes,including, but not limited to vacuum anneal processes, rapid thermalprocesses, etc. The support plates can be applied to the above thermalprocessing systems where one side (e.g., a backside) or both sides ofthe workpiece are exposed to one or more heat sources.

A thermal processing chamber can include a heat source to emit lightranging from an ultraviolet to a near infrared electromagnetic spectrum.In order to expose one side or both sides of a workpiece to the heatsource, the workpiece is supported by one or more support pins mountedonto a carrier structure, typically a base below the workpiece. Thesupport pins and the base form a support plate. In some configurations,the base is made from a highly transparent, uniform material (e.g.,quartz glass) as to not obstruct light from the heat sources. However,obstruction of light by the support pins cannot be avoided. As such,there can be a pin spot effect reducing the workpiece temperature atcontact areas of the workpiece in contact with the support pins.

During heating the workpiece, the workpiece is not in thermalequilibrium with walls and the support plate in the thermal processingchamber. Even though a thermal conduction of a material (e.g., a quartzmaterial) of a support pin is low and a contact area of the workpiece incontact with the support pin is small, there is still a cooling effectby the thermal conduction into the colder contact area associated withthe support pin. Additionally, in fast thermal transients (e.g., rapidthermal processing applications), added thermal mass of a support pincan cause a reduced heat up rate of the workpiece at the contact area.As a result, the workpiece temperature is reduced at the contact areaforming a cold spot. Typically, one or more cold spots can be left atone or more contact areas of the workpiece in contact with the supportplate. The cold spots can be caused by three main effects, such asshadowing, thermal conduction and higher thermal mass. According toexample aspects of the present disclosure, localized heating of thecontact areas can be used to compensate the cold spots left on theworkpiece.

An example aspect of the present disclosure is directed to a supportplate for localized heating in a thermal processing system to compensatecold spots on a workpiece. Localized heating is achieved by modifying aheat transmittance of a support plate such that one or more portions ofthe support plate proximate the areas that cause cold spots transmitmore heat than the rest of the support plate.

For example, the support plate can include a base and one or moresupport pins for contacting a workpiece during processing. One or moreheat sources (e.g., lamp, laser, or other heat sources) are used to heatthe workpiece. Localized heating is achieved by modifying an opticaltransmittance of the support plate such that the areas of the supportplate proximate (e.g., under and/or around, above and/or around, etc.)to the support pins transmit more light from the heat sources than therest of the support plate. For example, the optical transmittance of thesupport plate is modified such that only portions of the base where thesupport pins are joined to the base are unchanged with respect tountreated material (e.g., quartz glass) of the base. In portions of thebase away from the support pins, the optical transmittance is reduced bytreatment of the quartz glass of the base. The treatment to reduce theoptical transmittance can include grinding, coating, engraving, ordoping. The portions of the base with untreated quartz glass transmit ahigher heating flux relative to the portions of the base with treatedquartz glass. As such, the workpiece is exposed to a higher heating fluxfrom the portions of the base located proximate to the support pins,resulting in a compensation of cold spots caused by the support pins.

Another example aspect of the present disclosure is directed to athermal processing apparatus for localized heating in thermal processingsystems to compensate cold spots on the workpiece. The thermalprocessing apparatus includes one or more heat sources (e.g., lamps, orany other heat sources), a coherent light source (e.g., a laser, or anyother suitable source), and a rotatable support plate having a supportstructure (e.g., one or more support pins, or a ring support, etc.).Cold spots resulting from contact of the workpiece with the supportstructure can be compensated by heating the workpiece via the coherentlight source through the support structure in addition to heating theworkpiece globally by light from the heat sources. As such, the coldspots are heated locally by light from the coherent light source.

For example, in some embodiments, a cold spot is compensated by shininga beam of the coherent light (e.g., a laser beam) from the coherentlight source onto a support pin. The support pin is made from atransmissive material, such as quartz. The coherent light passes throughthe transmissive support pin to heat the portion of the workpiececontacting the support pin.

In some embodiments, the coherent light source is mounted to astationary part of the thermal processing apparatus such that thesupport pin is rotating through the coherent light during rotation ofthe support plate. The coherent light source, in some embodiments, canbe controlled to be switched on and off synchronized to the workpiecerotation as to only heat a contact area of the workpiece in contact withthe support pin. For instance, the coherent light source can becontrolled only to emit coherent light when the support pin passes infront of the coherent light source during rotation of the support plate.

In some embodiment, the synchronization can be accomplished by shapingthe power of the coherent light emitted from the light source. Forinstance, the power of the coherent light can be controlled to be at afirst value when the support pin is not passing in front of the coherentlight source. As the support pin approaches the coherent light source,the power of the coherent light can be increased. When the support pinpasses through the coherent light source, the power of the coherentlight can be controlled to be at a second value that is greater than thefirst value. As the support pin rotates away from the coherent lightsource, the power of the coherent light can be decreased, for instance,back to the first value or to a third value that is less than the secondvalue.

In some embodiments, this synchronization can be accomplished by anelectrical control circuit, where a trigger signal is generated from asensor signal indicative of a rotation orientation and a rotation speed.For example, based on known information of the rotation orientation andthe speed of the rotatable support plate or of the workpiece, anemission of the coherent light source can be synchronized with a motionof the rotatable support plate. The coherent light source emits coherentlight into the support pin and onto the workpiece when the support pinpasses over the coherent light source during rotation of the supportplate, and the coherent light source stops emitting the coherent lightwhen the support pin is not located in front of the coherent lightsource.

In some embodiments, localized heating can be achieved by modifying anoptical transmission of the base such that one or more portions of thebase that are proximate to the support pins transmit the coherent lightand the rest of the base is opaque to the coherent light from thecoherent light source. The opaque portions of the base can be generatedby grinding, coating, engraving, or doping. The opaque portions of thebase can be small as to not obstruct light from the heat sources. Insome embodiments, an opaque portion is a wavelength selective coating onone side (e.g., a backside) or both sides of the base in form of asemi-annular opaque portion (e.g., a segmented ring). The semi-annularopaque portions can extend between support pins along a path of coherentlight along the base during rotation of the support plate relative tothe coherent light source.

In some embodiments. a width of the semi-annual opaque portion can beless than or equal to a diameter of a contact area of the coherent lightin contact with the base. Examples of the contract area include a focalpoint of the coherent light onto the base, or a cross-section of thecoherent light in contact with the base. The wavelength sensitivecoating is selected such that only a narrow band of the coherent lightradiation is blocked, whereas a broad band light from the heat sourcesis almost completely transmitted, reducing an effect on a globaltemperature uniformity. As such, the synchronization of the coherentlight source to the rotatable support plate's rotation is inherentlybrought about by the rotatable support plate itself. In this exampleembodiment, the coherent light source can remain on and emit coherentlight during an entire heat cycle or relevant portions of the heatcycle.

In some embodiments, the support plate can include a ring support. Thering support can be a transmissive material (e.g., quartz) that allowsthe passage of coherent light from the coherent light source to heat theworkpiece. In this example embodiment, the coherent light source canremain on and emit coherent light during an entire heat cycle orrelevant portions of the heat cycle. The ring support can be mounted tothe base centered with respect to a center of the workpiece. A height ofthe ring support can be approximately the same as a height of a supportpin. Without additional heating, the ring support can cause a rotationalsymmetric cold pattern on the workpiece. By placing the coherent lightsource proximate to (e.g., below) the ring support, and by rotating theworkpiece and the ring support about its common center, the cold patternis compensated by a continuously emitting coherent light from thecoherent light source through the ring support onto the workpiece.

Aspects of the present disclosure can achieve a number of technicaleffects and benefits. For instance, aspects of the present disclosurecan reduce the presence of cold spots associated with support pins inthermal processing tools.

Variations and modifications can be made to these example embodiments ofthe present disclosure. As used in the specification, the singular forms“a,” “and,” and “the” include plural referents unless the contextclearly dictates otherwise. The use of “first,” “second,” “third,” and“fourth” are used as identifiers and are directed to an order ofprocessing. Example aspects may be discussed with reference to a“substrate,” “wafer,” or “workpiece” for purposes of illustration anddiscussion. Those of ordinary skill in the art, using the disclosuresprovided herein, will understand that example aspects of the presentdisclosure can be used with any suitable workpiece. The use of the term“about” in conjunction with a numerical value refers to within 20% ofthe stated numerical value.

With reference now to the FIGS., example embodiments of the presentdisclosure will now be discussed in detail. FIG. 1 depicts an examplerapid thermal processing (RTP) system 100 having a support plate 120with spatially arranged low transmission zones according to exampleembodiments of the present disclosure. As illustrated, the RTP system100 includes a RTP chamber 105, a workpiece 110, a support plate 120,heat sources 130 and 140, air bearings 145, a pyrometer 165, acontroller 175, a door 180, and a gas flow controller 185.

The workpiece 110 to be processed is supported in the RTP chamber 105(e.g., a quartz RTP chamber) by the support plate 120. The support plate120 supports the workpiece 110 during thermal processing. The supportplate 120 includes a rotatable base 135 and at least one supportstructure 115 extending from the rotatable base 135. A support structuredescribes a structure contacting and supporting a workpiece duringthermal processing. Examples of the support structure can include one ormore support pins, a ring support, or any other suitable support thatcontacts and supports a workpiece. As shown in FIG. 1, the supportstructure 115 includes one or more support pins (only one shown). Thesupport structure 115 and the rotatable base 135 can transmit heat fromthe heat sources 140 and to absorb heat from the workpiece 110. In someembodiments, the support structure 115 and the rotatable base 135 can bemade of quartz. The rotatable base 135 rotates the workpiece 110 at adefined rotation orientation and at a defined rotation speed, as furtherdescribed below.

A guard ring (not shown) can be used to lessen edge effects of radiationfrom one or more edges of the workpiece 110. An end plate 190 seals tothe chamber 105, and the door 180 allows entry of the workpiece 110 and,when closed, allows the chamber 105 to be sealed and a process gas 125to be introduced into the chamber 105. Two banks of heat sources (e.g.,lamps, or other suitable heat sources) 130 and 140 are shown on eitherside of the workpiece 110. The controller 175 (e.g., a computer,microcontroller(s), other control device(s), etc.) is used to controlthe heat sources 130 and 140. The controller 175 can be used to controlthe gas flow controller 185, the door 180, and/or the temperaturemeasuring system, denoted here as the pyrometer 165.

A gas flow 150 can be an inert gas that does not react with theworkpiece 110, or the gas flow 150 can be a reactive gas such as oxygenor nitrogen that reacts with the material of the workpiece 110 (e.g. asemiconductor wafer, etc.) to form a layer of on the workpiece 110. Thegas flow 150 can be a gas that can contain a silicon compound thatreacts at a heated surface of the workpiece 110 being processed to forma layer on the heated surface without consuming any material from thesurface of the workpiece 110. When the gas flow 150 reacts to form alayer on the surface, the process is called rapid thermal-chemical vapordeposition (RT-CVD). In some embodiments, an electrical current can berun through the atmosphere in the RTP system 100 to produce ions thatare reactive with or at the surface, and to impart extra energy to thesurface by bombarding the surface with energetic ions.

The controller 175 controls the rotatable base 135 to rotate theworkpiece 110. For example, the controller 175 generates an instructionthat defines the rotation orientation and the rotation speed of therotatable base 135, and controls the rotatable base 135 to rotate theworkpiece 110 with the defined rotation orientation and the definedrotation speed. The rotatable base 135 is supported by the air bearings145. The gas flow 150 impinging on the rotatable base 135 causes therotatable base 135 to rotate about an axis 155.

In some embodiments, the rotatable base 135 can have a first portionassociated with a first heat transmittance and a second portionassociated with a second heat transmittance. The second heattransmittance is different from the first heat transmittance. The secondportion is located proximate to the support pins 115. Examples of therotatable base 135 are further described below in conjunction with FIGS.2A and 2B.

FIGS. 2A and 2B depict an example support plate 200 with spatiallyarranged low transmission zones according to example embodiments of thepresent disclosure. In the embodiments of FIGS. 2A and 2B, the supportplate 200 includes three support pins 210 and a rotatable base 230. Moreor fewer support pins can be used without deviating from the scope ofthe present disclosure.

In some embodiments, the support plate 200 is an example embodiment ofthe support plate 120 (FIG. 1), and one support pin 210 is an embodimentof example support pin 115 (FIG. 1). Each support pin 210 has a firstend 212 and a second end 214. The first end 212 of the support pin 210contacts and supports a workpiece (not shown). The second end 214 of thesupport pin 210 contacts (e.g., is coupled to) the rotatable base 230.In some embodiments, the support pin(s) 210 can be integral with therotatable base 230.

As shown, the rotatable base 230 includes three circular areas 220. Eachcircular area 220 is located proximate to the second end 214 of onesupport pin 210. A diameter of one circular area 220 is greater than adiameter of a contact area of a corresponding support pin 210 contactingthe rotatable base 230. A center of one circular area 220 coincides witha center of a corresponding support pin 210. Remaining areas 240 of therotatable base 230 describe areas that exclude the three circular areas220 within the rotatable base 230. The remaining areas 240 areassociated with a first heat transmittance, and the three circular areas220 are associated with a second heat transmittance. The second heattransmittance can be different from the first heat transmittance. Forexample, the second heat transmittance can be higher than the first heattransmittance. The areas 240 are referred to as low transmission zonesthat have lower heat transmittance than the circular areas 220. As such,the circular areas 220 transmit more heat than the remaining areas 240to compensate cold spots that can be left on the workpiece supported bythe support pins 210. As a result, more uniform heat is distributed tothe workpiece via the support plate 200.

The present disclosure is discussed with areas 220 having a circularshape for purposes of illustration and discussion. Those of ordinaryskill in the art, using the disclosures provided herein, will understandthat areas 220 can have other shapes without deviating from the scope ofthe present disclosure.

In some embodiments, an optical transmittance of the support plate 200is modified such that the circular areas 220 are unchanged with respectto untreated material (e.g., untreated quartz) of the rotatable base230. The remaining areas can be treated material (e.g., treated quartz)having a reduced optical transmittance relative to the circular areas220. The treated quartz can be treated with one or more of grinding,coating, engraving, or doping. The circular areas 220 with untreatedquartz transmit a higher heating flux relative to the remaining areas240 with treated quartz. As such, the workpiece is exposed to a higherheating flux from the circular areas 220, resulting in a compensation ofcold spots caused by the support pins 210.

Aspects of the present disclosure are discussed with reference to asupport plate with one or more support pins as a support structure andwith a rotatable base for purposes of illustration and discussion. Thoseof ordinary skill in the art, using the disclosures provided herein,will understand that non-rotatable bases can be used without deviatingfrom the scope of the present disclosure. For example, a non-rotatablebase can have a first portion associated with a first heat transmittanceand a second portion associated with a second heat transmittance. Thesecond heat transmittance is different from the first heattransmittance, and the second portion is located proximate to a supportstructure (e.g., a support pin, a ring support, etc.). Those of ordinaryskill in the art, using the disclosures provided herein, will understandthat any support structure (e.g., a support pin, a ring support, asupport structure with an arbitrary shape, etc.) can be used withoutdeviating from the scope of the present disclosure

FIG. 3 depicts a flow diagram of a process (300) for heating a workpiecethrough a support plate with spatially arranged low transmission zonesaccording to example embodiments of the present disclosure. The process(300) can be implemented using the RTP system 100 of FIG. 1. However, aswill be discussed in detail below, the process (300) according toexample aspects of the present disclosure can be implemented using otherthermal processing systems without deviating from the scope of thepresent disclosure. FIG. 3 depicts steps performed in a particular orderfor purposes of illustration and discussion. Those of ordinary skill inthe art, using the disclosures provided herein, will understand thatvarious steps of any of the methods described herein can be omitted,expanded, performed simultaneously, rearranged, and/or modified invarious ways without deviating from the scope of the present disclosure.In addition, various additional steps (not illustrated) can be performedwithout deviating from the scope of the present disclosure.

At (310), the process can include placing a workpiece on a support platein a processing chamber. For example, in the embodiment of FIG. 1, thesupport plate 120 includes the support pins 115 and the rotatable base135. The workpiece 110 is placed on the support pins 115 in the RTPchamber 120 via the door 180. In some embodiments, the support plate 120can be used in an anneal processing chamber. For example, a workpiecefor annealing can be placed on the support plate 120 in the annealprocessing chamber. In some embodiments, the support plate 120 caninclude other support structures (e.g., a ring support, a supportstructure with an arbitrary shape, etc.). In some embodiments, thesupport plate 120 can include a non-rotatable base with spatiallyarranged low transmission zones.

At (320), the process can include rotating the workpiece with thesupport plate in the processing chamber. For example, in the embodimentof FIG. 1, the controller 175 instructs the rotatable base 135 to rotatethe workpiece 110 in the RTP chamber 105.

At (330), the process can include heating the workpiece with a pluralityof heat sources through the support plate. For example, in theembodiment of FIG. 1, the controller 175 controls the heat sources 140to heat the workpiece 110 through the rotatable base 135 and the supportbins 115 to a preset temperature.

At (340), the process can include removing the workpiece from thesupport plate. For example, in the embodiment of FIG. 1, the workpiece110 can be removed from the support bins 115 to exit from the RTPchamber 105 via the door 180.

FIG. 4 depicts an example RTP system 400 with a rotatable support plate410 and a coherent light source 430 according to example embodiments ofthe present disclosure. As illustrated, the RTP system 400 includes theRTP chamber 105, the workpiece 110, the rotatable support plate 410having support pins 415 and a base 420, a coherent light source 430, acontroller 440, heat sources 130 and 140, air bearings 145, thepyrometer 165, the door 180, and the gas flow controller 185.

The coherent light source 430 (e.g., a laser) can provide coherent light435 to the chamber 105. In some embodiments, the coherent light source430 is located external to the chamber 105 and transmits light 435 tothe chamber 105 via an optical pipe or light guide 435 (e.g., fiberoptic).

The rotatable support plate 410 supports the workpiece 110 duringthermal processing. The rotatable support plate 410 includes atransmissive support structure and a rotatable base 415. Thetransmissive support structure describes a structure that contacts andsupports the workpiece 110, and transmits light 435 from the coherentlight source 430 (e.g., a laser) to the workpiece 110 during thermalprocessing. Examples of the transmissive support structure can includeone or more support pins, a ring support, or any other suitable supportthat contacts and supports the workpiece 110, and transmits light to theworkpiece 110.

The transmissive support structure includes a first end and a secondend. The first end of the transmissive support plate is arranged tosupport the workpiece 110. The second of the transmissive support platecontacts (e.g., is coupled to) a first surface of the rotatable base420. In the example embodiment of FIG. 1, the transmissive supportstructure includes one or more support pins 415 (only one shown). Oneend of one support pin 415 contacts a backside of the workpiece 110, andthe other end of the support pin 415 contacts a surface of the base 420.The base 420 rotates the workpiece 110 at a defined rotation orientationand at a defined rotation speed based on an instruction received fromthe controller 440, as further described below.

In some embodiments, the transmissive support structure and the base 420can transmit heat from the heat sources 140 and to absorb heat from theworkpiece 110. For example, the transmissive support structure and thebase 420 can be made of quartz.

In some embodiments, the rotatable support plate 410 includes one ormore support pins 415, and the base 420 having a semi-annular opaqueportion (shown in FIGS. 5 and 6) disposed between at least two of thesupport pins 415. The semi-annular opaque portion can obstruct coherentlight of the coherent light source 430 from heating the workpiece 110such that the coherent light source 430 can continuously emit thecoherent light into onto the base 420 during the rotation of theworkpiece 110.

In some embodiments, the rotatable support plate 410 includes a ringsupport (shown in FIG. 7) and the base 420. For example, both the ringsupport and the base 420 can be a transmissive material (e.g., quartz)that allows the passage of coherent light continuously emitted from thecoherent light source 430 to heat the workpiece 110

The coherent light source 430 emits coherent light 435 through therotatable base 420 and the transmissive support structure such that thecoherent light heats a portion of the workpiece 110 contacting thetransmissive support structure. Examples of the coherent light source430 can include a continuous wave laser, a pulsed laser, or othersuitable light source emitting coherent light.

In the example embodiment of FIG. 4, the coherent light source 430 ismounted to a stationary part of the RTP chamber 105 such that thesupport pin 415 is rotating through the coherent light 435 duringrotation of the rotatable support plate 410. The coherent light source430 emits coherent light 435 onto a backside of the base 420, and theemitted coherent light can pass through the support pin 415 to heat acontact area of the workpiece 110 contacting the support pin 415. Assuch, a cold spot resulting from contact of the workpiece 110 with thesupport pin 415 can be compensated by heating the workpiece 110 via thecoherent light source 430 through the support pin 415 in addition toheating the workpiece 110 globally by light from the heat sources 140.In some embodiments, the coherent light source 430 is controlled by thecontroller 440 to be switched on and off synchronized to the workpiece110 rotation as to heat a contact area of the workpiece in contact withthe support pin 415. The controller 440 controls one or more of therotatable base 415, the coherent light source 430, the heat sources 130and 140, the gas flow controller 185, the door 180, and the pyrometer165. The controller 440 controls the base 420 to rotate the workpiece110 with a defined rotation orientation and a defined rotation speed.For example, the controller 440 generates an instruction that defines arotation orientation and a rotation speed of the base 420, and controlsthe base 420 to rotate the workpiece 110 with the defined rotationorientation and the defined rotation speed. In some embodiments, thecontroller 440 controls the coherent light source 430 to emit coherentlight 435 based on the rotation orientation and the rotation speed ofthe base 420. For example, the controller 440 can include an electricalcontrol circuit that generates a trigger signal to trigger the coherentlight source 430 to emit coherent light 435 based on a sensor signalindicative of a rotation orientation and a rotation speed of the base420.

In some embodiments, the controller 440 synchronizes an emission of thecoherent light from the coherent light source 430 with a motion of thebase 420 such that the coherent light source 430 emits the coherentlight into one of the support pins 415 and onto the workpiece 110 whenthat support pin 415 passes over the coherent light source 430 duringrotation of the base 420, and such that the coherent light source 430stops emitting the coherent light when that support pin 415 is notlocated in front of the coherent light source 430. For example, thecontroller 440 generates an instruction that instructs the coherentlight source 430 to emit coherent light based on a rotation orientationand a rotation speed of the base 420. The instruction can include acommand that instructs the coherent light source 430 to emit coherentlight, a command that instructs the coherent light source 430 to stopemitting the coherent light, a command that calculates a time intervalbetween an emission and a subsequent emission of the coherent lightsource 430 based on the rotation orientation and the rotation speed ofthe workpiece 110, etc.

In some embodiments, the controller 440 controls the coherent lightsource 430 to continuously emit the coherent light into the transmissivesupport structure. For example, the controller 440 generates aninstruction that instructs the coherent light source 430 to remain onand continuously emit the coherent light onto the base 420. The base 420can include a semi-annular opaque portion obstructing coherent light ofthe coherent light source 430 from heating portions the workpiece 110not in contact with the support structure. When the support pin 415 isnot located in front of the coherent light source 430, the controller440 instructs the coherent light 430 to remain on and to continuouslyemit coherent light onto the semi-annular opaque portion such that theemitted coherent light is blocked by the semi-annular opaque portion.When the support pin 415 passes in front of the continuously emittedcoherent light, the coherent light passes through the support pin 415 toheat the workpiece 110.

In another example, the controller 440 generates an instruction thatinstructs the coherent light source 430 to remain on and continuouslyemit the coherent light onto the rotatable support plate 410 with a ringsupport. During the rotation of the workpiece 110, the ring supportalways passes over the coherent light source 430 and transmits thecoherent light to heat the workpiece 110. The controller 440 instructsthe coherent light source 430 to continuously emit the coherent lightinto the ring support. As such, a cold pattern caused by the ringsupport is compensated by continuously shining the coherent light fromthe coherent light source 430 through the ring support onto workpiece110.

FIG. 5 depicts an example base 500 with spatially arranged lowtransmission zones according to example embodiments of the presentdisclosure. In the embodiment of FIG. 5, the base 500 can be anembodiment of the base 420. The base 500 includes three round-shapeportions 510, multiple semi-annular opaque portions 520, and remainingportions 530. One round-shape portion 510 is a contact area of aworkpiece contacting a support pin (not shown). Each semi-annular opaqueportion is disposed between any two of the three round-shape portions510. The remaining portions 530 of the base 500 describe portions thatexclude the three round-shape portions 510 and multiple semi-annularopaque portions 520 within the base 500.

FIG. 6 depicts an example of coherent light 610 heating the workpiece110 through the base 500 and the support pin 415 according to exampleembodiments of the present disclosure. The coherent light 610 is emittedfrom a coherent light source (not shown). The coherent light 610 passesthrough the support pin 415 to heat the workpiece 110. When the base 500rotates, the support pin 415 is not located in front of the coherentlight 610, but one semi-annular opaque portion 520 passes over thecoherent light 610 and obstructs the coherent light 610 to heat theworkpiece 110. As such, cold spots are compensated by shining acontinuously emitting coherent light onto each support pin during therotation of the base 500.

In the embodiment of FIGS. 5 and 6, a width of the semi-annular opaqueportion 520 is not less than a diameter of a contact area of thecoherent light 610 in contact with the base 500. Examples of thecontract area of the coherent light 610 include a focal point of thecoherent light 610 onto the base 500, or a cross-section of the coherentlight 610 contacting the base 500. The round-shape portions 510 and theremaining portions 530 can be unchanged with respect to untreatedmaterial (e.g., untreated quartz) of the base 500. The semi-annularopaque portions 520 can be treated material (e.g., treated quartz) thatobstructs coherent light of a coherent light source (not shown) fromheating the workpiece 110. The treated material can be treated with oneor more of grinding, coating, engraving, or doping. In some embodiments,the semi-annular opaque portions 520 includes a wavelength selectivecoating on one side (e.g., a backside) or both sides of the base 500.The wavelength sensitive coating is selected such that only a narrowband of the coherent light radiation is blocked, whereas a broad bandlight from the heat sources is almost completely transmitted, reducingan effect on a global temperature uniformity.

In some embodiments, the semi-annular opaque portions 520 can extendbetween support pins 415 along a path of coherent light 610 along thebase 500 during rotation of the base 500 relative to a coherent lightsource (not shown). The semi-annular opaque portions 520 can be small asto not obstruct light from heat sources (not shown). The semi-annularopaque portions 520 are also referred to low transmission zones thatobstruct coherent light to heat a workpiece.

Aspects of the present disclosure are discussed with reference to arotatable support plate with three support pins as transmissive supportstructures for purposes of illustration and discussion. Those ofordinary skill in the art, using the disclosures provided herein, willunderstand that multiple disconnected supports with a rotatablesymmetric arrangement can be used without deviating from the scope ofthe present disclosure. For example, multiple supports are not connectedwith each other, but these multiple supports are arranged in rotatablesymmetric pattern on the base. A support can have an arbitrary shape.

FIG. 7 depicts an example rotatable support plate 700 with a ringsupport 720 according to example embodiments of the present disclosure.In the embodiment of FIG. 7, the rotatable support 700 can be anembodiment of the rotatable support plate 410. The rotatable support 700includes a rotatable base 710 and the ring support 720. The ring support720 is centered with respect to a center of the rotatable base 710. Insome embodiments, the ring support 720 is centered with respect to acenter of a workpiece (not shown) contacting the ring support 720. Awidth of the ring support 720 is not less than a diameter of a contactarea of the coherent light (not shown) in contact with the ring support720. Examples of the contact area of the coherent light include a focalpoint of the coherent light onto the ring support 720, or across-section of the coherent light contacting the ring support 720. Insome embodiments, a height of the ring support 710 can be approximatelythe same as a height of the support pin 415. In some embodiments, boththe rotatable base 710 and the ring support 720 can be a transmissivematerial (e.g., untreated quartz) that allows the passage of coherentlight from a coherent light source to heat a workpiece. As such, acoherent light source can continuously emit coherent light that passesthrough the rotatable base 710 and the ring support 720 to heat aworkpiece contacting the ring support 720. Additionally, a cold patterncaused by the ring support 720 can be compensated by a continuouslyemission from the coherent light source to heat the workpiece.

Aspects of the present disclosure are discussed with reference to arotatable support plate with a ring support as a transmissive supportstructure for purposes of illustration and discussion. Those of ordinaryskill in the art, using the disclosures provided herein, will understandthat any transmissive support structure with a rotatable symmetric shapecan be used without deviating from the scope of the present disclosure.

FIG. 8 depicts a flow diagram of a process (800) for heating a workpiecebased on a rotatable support plate and a coherent light source accordingto example embodiments of the present disclosure. The process (800) canbe implemented using the RTP system 400. However, as will be discussedin detail below, the process (800) according to example aspects of thepresent disclosure can be implemented using other thermal processingsystems without deviating from the scope of the present disclosure. FIG.8 depicts steps performed in a particular order for purposes ofillustration and discussion. Those of ordinary skill in the art, usingthe disclosures provided herein, will understand that various steps ofany of the methods described herein can be omitted, expanded, performedsimultaneously, rearranged, and/or modified in various ways withoutdeviating from the scope of the present disclosure. In addition, variousadditional steps (not illustrated) can be performed without deviatingfrom the scope of the present disclosure.

At (810), the process can include placing a workpiece on a rotatablesupport plate in a processing chamber. The rotatable support plateincludes a transmissive support structure and a base. For example, inthe embodiment of FIG. 4, the rotatable support plate 410 includessupport pins 415 and the base 420. The workpiece 110 is placed on thesupport pins 415 in the RTP chamber 105 through the door 180. In someembodiments, the rotatable support plate 410 can be used in an annealprocessing chamber. For example, a workpiece for annealing can be placedon the rotatable support plate 410 in the anneal processing chamber.

At (820), the process can include heating the workpiece using one ormore heat sources. For example, in the embodiment of FIG. 4, thecontroller 440 controls the heat sources 140 to heat the workpiece 110through the base 420 and the support bins 415 to a preset temperature.

At (830), the process can include rotating the workpiece with therotatable support plate relative to the one or more heat sources duringheating of the workpiece. For example, in the embodiment of FIG. 4, thecontroller 440 instructs the base 420 to rotate the workpiece 110 in theRTP chamber 105 with a defined rotation orientation and a definedrotation speed.

At (840), the process can include emitting coherent light from acoherent light source through the base and the transmissive supportstructure such that the coherent light heats a portion of the workpiececontacting the transmissive support structure. For example, in theembodiment of FIG. 4, the controller 440 synchronizes an emission of thecoherent light from the coherent light source 430 with a motion of thebase 420 such that the coherent light source 430 emits the coherentlight into one of the support pins 415 and onto the workpiece 110 whenthat support pin 415 passes over the coherent light source 430 duringrotation of the base 420, and such that the coherent light source 430stops emitting the coherent light when that support pin 415 is notlocated in front of the coherent light source 430. In another example,the controller 440 controls the coherent light source 430 tocontinuously emit the coherent light to heat workpiece 110 through therotatable support plate 410 (e.g., a rotatable support plate withsupport pins 415 and the base 500 in FIGS. 5 and 6, or the rotatablesupport plate 700 in FIG. 7).

At (850), the process can include removing the workpiece from therotatable support plate. For example, in the embodiment of FIG. 4, theworkpiece 110 can be removed from the support bins 415 to exit from theRTP chamber 105 via the door 180.

Aspects of the present disclosure are discussed with reference to arotatable support plate. Those of ordinary skill in the art, using thedisclosures provided herein, will understand that example aspects of thepresent disclosure can be implemented with a stationary support plate.For instance, one or more coherent light sources can be positioned inview of a support pin on the stationary support plate. The coherentlight source can emit coherent light onto the stationary support plateand through the support pin for cold spot reduction on the workpiece.

While the present subject matter has been described in detail withrespect to specific example embodiments thereof, it will be appreciatedthat those skilled in the art, upon attaining an understanding of theforegoing may readily produce alterations to, variations of, andequivalents to such embodiments. Accordingly, the scope of the presentdisclosure is by way of example rather than by way of limitation, andthe subject disclosure does not preclude inclusion of suchmodifications, variations and/or additions to the present subject matteras would be readily apparent to one of ordinary skill in the art.

What is claimed is:
 1. A thermal processing apparatus, comprising: aplurality of heat sources configured to heat a workpiece; a rotatablesupport plate operable to support the workpiece during thermalprocessing, the rotatable support plate comprising: a transmissivesupport structure configured to contact the workpiece, the transmissivesupport structure comprising a first end and a second end, wherein thefirst end of the support structure is arranged to support the workpiece;and a light source operable to emit coherent light through thetransmissive support structure such that the coherent light heats aportion of the workpiece contacting the transmissive support structure.2. The thermal processing apparatus of claim 1, wherein the transmissivesupport structure is configured to transmit heat from the plurality ofheat sources to the workpiece.
 3. The thermal processing apparatus ofclaim 1, wherein the transmissive support structure comprises a quartzmaterial.
 4. The thermal processing apparatus of claim 1, wherein thelight source is configured to be maintained stationary relative to therotatable support plate during rotation of the rotatable support plateduring thermal processing of the workpiece.
 5. The thermal processingapparatus of claim 1, wherein the light source comprises a laser.
 6. Thethermal processing apparatus of claim 1, wherein the transmissivesupport structure comprises a plurality of support pins.
 7. The thermalprocessing apparatus of claim 1, wherein the transmissive supportstructure comprises a base, the base having a semi-annular opaqueportion disposed between at least two of the plurality of support pins,the semi-annular opaque portion configured to obstruct the coherentlight of the light source from heating the workpiece.
 8. The thermalprocessing apparatus of claim 7, wherein a width of the semi-annularopaque portion is not less than a diameter of a contact area of thecoherent light in contact with the base.
 9. The thermal processingapparatus of claim 7, wherein the semi-annular opaque portion comprisesa wavelength selective coating on the second surface of the base. 10.The thermal processing apparatus of claim 1, further comprising acontroller configured to synchronize an emission of the coherent lightfrom the light source with a motion of the base such that the lightsource emits the coherent light into one of the plurality of supportpins and onto the workpiece when one of the plurality of support pinspasses over the light source during rotation of the support plate, andsuch that the light source stops emitting the coherent light when one ofthe plurality of support pins is not located in front of the lightsource.
 11. The thermal processing apparatus of claim 1, wherein thetransmissive support structure comprises a ring support.
 12. The thermalprocessing apparatus of claim 11, wherein the ring support is centeredwith respect to a center of the workpiece.
 13. The thermal processingapparatus of claim 11, wherein a width of the ring support is not lessthan a diameter of a contact area of the coherent light in contact withthe ring support.
 14. The thermal processing apparatus of claim 11,further comprising a controller configured to control the coherent lightsource to continuously emit the coherent light into the ring support.15. A support plate for supporting a workpiece in a thermal processingapparatus, the support plate comprising: a base; at least one supportstructure extending from the base, the at least one support structureconfigured to support the workpiece during thermal processing; whereinthe base comprises a first portion associated with a first heattransmittance and a second portion associated with a second heattransmittance, the second heat transmittance being different from thefirst heat transmittance, wherein the second portion is locatedproximate to the at least one support structure.
 16. The support plateof claim 15, wherein the at least one support structure comprises asupport pin.
 17. The support plate of claim 16, wherein the secondportion comprises a circular area located where the support pin contactsthe base, wherein a diameter of the circular area is greater than adiameter of the support pin.
 18. The support plate of claim 15, whereinthe second portion comprises untreated quartz, and the first portioncomprises treated quartz, wherein the treated quartz has reduced opticaltransmittance relative to the second portion.
 19. The support plate ofclaim 18, wherein the treated quartz is treated with one or more ofgrinding, coating, engraving, or doping.
 20. A process for heating aworkpiece in a processing chamber, comprising: placing the workpiece ona support plate in the processing chamber, the support plate operable tosupport the workpiece during thermal processing, the support platecomprising: a base; at least one support structure extending from thebase, the at least one support structure configured to support theworkpiece during thermal processing; wherein the base comprises a firstportion associated with a first heat transmittance and a second portionassociated with a second heat transmittance, the second heattransmittance being different from the first heat transmittance, whereinthe second portion is located proximate to the at least one supportstructure; and heating the workpiece with a plurality of lamp heatsources through the base and the at least one support structure.